The present invention relates to an interlock for the throttle and parking brake of a vehicle and in particular, to a system for maintaining the vehicle engine at a predetermined speed when the parking brake is actuated, and for enabling the vehicle operator to control engine speed when the parking brake is deactuated.
It is well recognized that, in the operation of operator controlled vehicles, it is desirable to include a parking brake-throttle interlock. The inclusion of the described interlock feature prevents the operator or other persons from inadvertently attempting to move the vehicle while the parking brake is engaged. Essentially, the interlock maintains the engine used to drive the vehicle at a predetermined speed, for example, idle, when the parking brake is engaged.
There are several known systems which have heretofore been employed to protect against the unintentional application of power to a vehicle while the parking brake is engaged. One of the prior art systems utilizes a flexible connection, such as a Bowden-type cable, to activate an accelerator pedal jamming mechanism when the parking brake is applied. This type of system is rather difficult to install and relatively expensive to mount. Further, Bowden-type cables are susceptible to loss of effectiveness from kinking or corrosion caused by weather related elements. Other systems eliminate the use of the flexible connector by using rather complex systems of shafts, bellcranks, levers, and other rigid members. Not only are such systems complex, but they require a rather close proximity of the parking brake actuator and the control used to regulate engine speed. Essentially, such systems are limited to use on mechanically applied parking brakes and power control linkages, and are not applicable for use on hydraulic, pneumatic, or other remote controlled parking brake and power control systems.
Accordingly, it is an object of this invention to provide an interlock for the throttle and parking brake of a vehicle which may be utilized from pneumatic, hydraulic or other remote controlled parking brake and power control systems. It is a further object of the interlock design to reduce the complexity of the design and to minimize the interlock's susceptibility to damage.